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Abstract Abyssal manganese nodules have been explored widely for their economic potential and paleoenvironmental significance. Debate about whether biogenic or physical‐chemical processes are responsible for their formation remains because of difficulties in quantifying ancient microbiological contributions. To address this question, we investigated microbial fossils in manganese nodules from the western Pacific Ocean by integrating scanning electron microscope, transmission electron microscope, and synchrotron transmission X‐ray microscope observations. Our results suggest that the nodules host abundant fossil biogenic magnetite and manganese‐oxidizing bacteria. These organisms engage in redox reactions or live in environments with redox gradients. By combining magnetic properties and observations of fossil biogenic magnetite morphology, we estimate magnetofossil abundances and further assess fossil biogenic manganese oxide in nodules. Our results imply that manganese nodule formation appears to be dominated by biomineralization with an additional terrestrial contribution. Extensive biomineralization in ultralow‐productivity oceanic environments suggests that manganese nodule formation is an important aspect of biogeochemical cycling in abyssal seafloor environments.

The northwestern Pacific Ocean and South China Sea are where tropical cyclones occur most frequently. Many climatologists also study the formation of Pacific Ocean warm pools and typhoons in this region. This study collected data of paleotyphoons found in China's official historical records over the past 2000 years that contained known typhoon activity reports. The collected data are then subjected to statistical analyses focusing on typhoon activity in coastal regions of southeastern China to garner a better understanding of the long-term evolution of moving paths and occurrence frequency, especially regarding those typhoons making landfall in mainland China. We analyzed the data with the year and month of each typhoon event, as well as the number of events in a 10-year period. The result shows that (1) north–southward migration of typhoon paths corresponds to the north–southward migration of the Intertropical Convergence Zone (ITCZ) during the Medieval Warm Period (MWP) and Little Ice Age (LIA) and (2) paleotyphoons made landfall in mainland China 1 month earlier during the MWP than during the LIA. This implies a northward shift in ITCZ during the MWP. Typhoons tend to make landfall in Japan during El Niño-like periods and strike the southern coastal regions of China during La Niña-like stages. According to paleotyphoon records over the last 2000 years, typhoons made landfall in southeastern China frequently around 490–510, 700–850, and after 1500 CE The number of typhoons striking Guangdong Province peaked during the coldest period in 1660–1680 CE; however, after 1700 CE, landfall has migrated farther north. The track of tropical cyclones (TCs) in the northwestern Pacific Ocean is affected by the North Atlantic Oscillation (NAO) and the Pacific Decadal Oscillation (PDO), which shows a nearly 30-year and a 60-year cycle during the LIA.